Coated abrasive article and method of making the same

ABSTRACT

A coated abrasive article comprises a backing having first and second opposed major surfaces, a make layer disposed on at least a portion of the first major surface and bonding abrasive particles to the backing, a size layer overlaid on at least a portion of the make layer and the abrasive particles, and a supersize layer disposed on the size layer. The supersize layer comprises an at least partially cured water-based epoxy resin and an organic polymeric rheology modifier, and wherein the amount of the at least partially cured epoxy resin comprises from 75 to 99.99 weight percent of the combined weight of the at least partially cured epoxy resin and the organic polymeric rheology modifier. A method of making the coated abrasive article is also disclosed.

TECHNICAL FIELD

The present disclosure relates to abrasive articles including an epoxy supersize binder material, and methods of making the same.

BACKGROUND

Abrasive articles generally comprise abrasive particles (also known as “grains”) retained within a binder. During manufacture of various types of abrasive articles, the abrasive particles are deposited on a binder material precursor in an oriented manner (e.g., by electrostatic coating or by some mechanical placement technique). Typically, the most desirable orientation of the abrasive particles is substantially perpendicular to the surface of the backing.

In the case of certain coated abrasive articles (e.g., grinding discs), the backing is a relatively dense planar substrate (e.g., vulcanized fiber or a woven or knit fabric, optionally treated with a saturant to increase durability). A make layer precursor (or make coat) containing a first binder material precursor is applied to the backing, and then the abrasive particles are partially embedded into the make layer precursor. Frequently, the abrasive particles are embedded in the make layer precursor with a degree of orientation; e.g., by electrostatic coating or by a mechanical placement technique. The make layer precursor is then at least partially cured in order to retain the abrasive particles when a size layer precursor (or size coat) containing a second binder material precursor is overlaid on the at least partially cured make layer precursor and abrasive particles. Next, the size layer precursor, and the make layer precursor if not sufficiently cured, are cured to form the coated abrasive article.

In some instances, a supersize layer, which may be formed from a corresponding supersize layer precursor, the size layer.

For thermally cured supersize layer precursors, the coated abrasive product is often manufactured as a continuous web that is dried and cured in festoon ovens, where the web is draped over hanger bars that progress through the oven.

SUMMARY

Flow of the supersize layer due to gravity can be a problem during curing in a festoon oven, especially if the abrasive particles are aligned such that flow is not impeded by the abrasive particles. However, the recent trend toward precise placement and/or orientation of the abrasive particles has increased the need for a solution to the gravity flow problem discussed above.

The present disclosure overcomes this problem by using a supersize layer precursor containing a water-based curable epoxy resin and a rheology modifier suitable for use in manufacture of an abrasive article. The rheology modifier comprises an organic polymeric rheology modifier comprising an alkali-swellable/soluble polymer. These organic polymeric rheology modifiers are presently discovered to provide better control of supersize layer precursor flow than the techniques previously used.

Organic polymeric rheology modifiers are known to give pseudoplastic flow characteristics. Particularly, Alkali-Swellable/soluble Emulsion (ASE) polymers, Hydrophobically-modified Alkali-Swellable/soluble Emulsion (HASE) polymers, and Hydrophobically-modified Ethoxylated URethane (HEUR) polymers have been used in aqueous compositions for latex paints, personal care products, and drilling muds. As used herein, the term “Alkali-Swellable/soluble Emulsion (ASE) polymers” expressly excludes Hydrophobically-modified Alkali-Swellable/soluble Emulsion (HASE) polymers.

In a first aspect, the present disclosure provides a method of making a coated abrasive article, the method comprising:

-   -   providing a backing having first and second opposed major         surfaces, wherein a make layer is disposed on at least a portion         of the first major surface and bonds abrasive particles to the         backing, and further wherein a size layer is disposed over at         least a portion of the make layer and the abrasive particles;         and     -   coating a supersize layer precursor over at least a portion of         the size layer and at least partially curing the supersize layer         precursor to provide a supersize layer,     -   wherein the supersize layer precursor comprises a water-based         epoxy resin and an organic polymeric rheology modifier, wherein         the organic polymeric rheology modifier comprises an         alkali-swellable/soluble polymer, and, wherein on a solids         basis, the amount of the water-based epoxy resin comprises from         75 to 99.99 weight percent of the combined weight of the         water-based epoxy resin and the organic polymeric rheology         modifier.

In a second aspect, the present disclosure provides a coated abrasive article comprising:

-   -   a backing having first and second opposed major surfaces,     -   a make layer disposed on at least a portion of the first major         surface and bonding abrasive particles to the backing;     -   a size layer overlaid on at least a portion of the make layer         and the abrasive particles; and     -   a supersize layer disposed on the size layer,     -   wherein the supersize layer comprises an at least partially         cured epoxy resin and an organic polymeric rheology modifier,         and wherein the amount of the at least partially cured epoxy         resin comprises from 75 to 99.99 weight percent of the combined         weight of the at least partially cured epoxy resin and the         organic polymeric rheology modifier.

As used herein:

-   -   “alkali-swellable” means at least partially swellable in an         aqueous solution of a water-soluble base having a pH of greater         than 7;     -   “alkali-swellable/soluble” means at least one of         alkali-swellable or alkali-soluble (i e, alkali-swellable and/or         alkali-soluble);     -   “polymer” refers to an organic polymer unless otherwise clearly         indicated; and     -   “water-based” means dissolved or dispersed in a liquid medium         having water as its major constituent.

Features and advantages of the present disclosure will be further understood upon consideration of the detailed description as well as the appended claims

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional side view of an exemplary coated abrasive article 100 according to the present disclosure.

FIG. 2 is a schematic perspective view of exemplary precisely-shaped abrasive particle 200.

FIG. 3 is a digital photograph of a coated abrasive article made with Comparative Supersize Layer Precursor CSSR-F.

FIG. 4 is a digital photograph of a coated abrasive article made with Supersize Layer Precursor ESSR-5.

It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale.

DETAILED DESCRIPTION

An exemplary embodiment of a coated abrasive article according to the present disclosure is depicted in FIG. 1 . Referring now to FIG. 1 , coated abrasive article 100 has backing 120 and abrasive layer 130. Abrasive layer 130 includes abrasive particles 140 secured to major surface 170 of backing 120 by make layer 150 and size layer 160. Supersize layer 180 overlays size layer 160.

Coated abrasive articles according to the present disclosure may include additional layers such as, for example, a backing antistatic treatment layer and/or an attachment layer may also be included, if desired.

Useful backings include, for example, those known in the art for making coated abrasive articles. Typically, the backing has two opposed major surfaces, although this is not a requirement. The thickness of the backing generally ranges from about 0.02 to about 5 millimeters, desirably from about 0.05 to about 2.5 millimeters, and more desirably from about 0.1 to about 1.0 millimeter, although thicknesses outside of these ranges may also be useful. Generally, the strength of the backing should be sufficient to resist tearing or other damage during abrading processes. The thickness and smoothness of the backing should also be suitable to provide the desired thickness and smoothness of the coated abrasive article; for example, depending on the intended application or use of the coated abrasive article.

Exemplary backings include dense nonwoven fabrics (e.g., needletacked, meltspun, spunbonded, hydroentangled, or meltblown nonwoven fabrics), knitted fabrics, stitchbonded and/or woven fabrics; scrims; polymer films; treated versions thereof; and combinations of two or more of these materials.

Fabric backings can be made from any known fibers, whether natural, synthetic or a blend of natural and synthetic fibers. Examples of useful fiber materials include fibers or yarns comprising polyester (e.g., polyethylene terephthalate), polyimide (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, vinyl chloride-acrylonitrile copolymers, graphite, polyimide, silk, cotton, linen, jute, hemp, or rayon. Useful fibers may be of virgin materials or of recycled or waste materials reclaimed from garment cuttings, carpet manufacturing, fiber manufacturing, or textile processing, for example. Useful fibers may be homogenous or a composite such as a bicomponent fiber (for example, a co-spun sheath-core fiber). The fibers may be tensilized and crimped, but may also be continuous filaments such as those formed by an extrusion process.

The backing may have any suitable basis weight; typically, in a range of from 100 to 1250 grams per square meter (gsm), more typically 450 to 600 gsm, and even more typically 450 to 575 gsm. In many embodiments (e.g., abrasive belts and sheets), the backing typically has good flexibility; however, this is not a requirement (e.g., vulcanized fiber discs). To promote adhesion of binder resins to the backing, one or more surfaces of the backing may be modified by known methods including corona discharge, ultraviolet light exposure, electron beam exposure, flame discharge, and/or scuffing.

The make layer is formed by coating a make layer precursor on a major surface of the backing and at least partially curing the make layer precursor. The make layer precursor comprises a thermosetting/curable composition. Examples of suitable thermosetting/curable resins that may be useful for the make layer precursor include, for example, free-radically polymerizable monomers and/or oligomers, epoxy resins, acrylic resins, urethane resins, phenolic resins, urea-formaldehyde resins, melamine-formaldehyde resins, aminoplast resins, cyanate resins, and combinations thereof. Useful binder precursors include thermally curable resins and radiation curable resins, which may be cured, for example, thermally and/or by exposure to radiation. Depending on the curable resin, it is typical to include a catalyst and/or initiator (e.g., a thermal initiator and/or a photoinitiator) in amounts up to 10 weight percent of the make layer precursor. Selection of catalysts and/or initiators is within the capability of those having ordinary skill in the art. Additional details concerning make layer precursors may be found in U.S. Pat. No. 4,588,419 (Caul et al.), U.S. Pat. No. 4,751,138 (Tumey et al.), and U.S. Pat. No. 5,436,063 (Follett et al.).

The make layer precursor and the make layer may be modified by various additives (e.g., fibers, lubricants, wetting agents, surfactants, pigments, dyes, antistatic agents (e.g., carbon black, vanadium oxide, and/or graphite), coupling agents (e.g., silanes, titanates, zircoaluminates, etc.), plasticizers, suspending agents).

In some embodiments, the make layer precursor comprises a resole phenolic resin and an organic polymeric rheology modifier. The organic polymeric rheology modifier comprises an alkali-swellable/soluble polymer. On a solids basis, the amount of the resole phenolic resin comprises from 75 to 99.99 weight percent of the combined weight of the resole phenolic resin and the organic polymeric rheology modifier.

The organic polymeric rheology modifier comprises an alkali-swellable/soluble polymer. On a solids basis, the amount of the resole phenolic resin comprises from 75 to 99.99 weight percent of the combined weight of the resole phenolic resin and the organic polymeric rheology modifier.

Phenolic resins are generally formed by condensation of phenol and formaldehyde, and are usually categorized as resole or novolac phenolic resins. Novolac phenolic resins are acid-catalyzed and have a molar ratio of formaldehyde to phenol of less than 1:1. Resole (also resol) phenolic resins can be catalyzed by alkaline catalysts, and the molar ratio of formaldehyde to phenol is greater than or equal to one, typically between 1.0 and 3.0, thus presenting pendant methylol groups Alkaline catalysts suitable for catalyzing the reaction between aldehyde and phenolic components of resole phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, and sodium carbonate, all as solutions of the catalyst dissolved in water.

Resole phenolic resins are typically coated as a solution with water and/or organic solvent (e.g., alcohol). Typically, the solution includes about 70 percent to about 85 percent solids by weight, although other concentrations may be used. If the solids content is very low, then more energy is required to remove the water and/or solvent. If the solids content is very high, then the viscosity of the resulting phenolic resin is too high which typically leads to processing problems.

Phenolic resins are well-known and readily available from commercial sources. Examples of commercially available resole phenolic resins useful in practice of the present disclosure include those marketed by Durez Corporation under the trade designation VARCUM (e.g., 29217, 29306, 29318, 29338, 29353); those marketed by Ashland Chemical Co. of Bartow, Fla. under the trade designation AEROFENE (e.g., AEROFENE 295); and those marketed by Kangnam Chemical Company Ltd. of Seoul, South Korea under the trade designation PHENOLITE (e.g., PHENOLITE TD-2207).

A general discussion of phenolic resins and their manufacture is given in Kirk-Othmer, Encyclopedia of Chemical Technology, 4th Ed., John Wiley & Sons, 1996, New York, Vol. 18, pp. 603-644.

In addition to the resole phenolic resin, the curable composition contains an organic polymeric rheology modifier that comprises an alkali-swellable/soluble polymer. The curable composition comprises a resole phenolic resin (typically diluted with water) and an organic polymeric rheology modifier that comprises an alkali-swellable/soluble polymer. On a solids basis, wherein the amount of the resole phenolic resin comprises from 75 to 99.99 weight percent (preferably 82 to 99.99 weight percent, and even more preferably 88 to 99.99 weight percent) of the combined weight of the resole phenolic resin and the organic polymeric rheology modifier. Accordingly, the curable composition contains from 0.01 to 25 weight percent, preferably 0.01 to 18 weight percent, and more preferably 0.01 to 12 weight percent of the organic polymeric rheology modifier, based on the combined weight of the resole phenolic resin and the organic polymeric rheology modifier. Combinations of more than one resole phenolic resin and/or more than one organic polymeric rheology modifier may be used if desired.

Alkali-swellable/soluble polymers suitable for use as the organic polymeric rheology modifier include, for example, Alkali-Swellable/soluble Emulsion (ASE) organic polymers, Hydrophobically-modified Alkali-Swellable/soluble Emulsion polymers (HASE), and Hydrophobically modified Ethoxylated URethane polymers (HEUR).

The organic polymeric rheology modifier may be chosen from alkali-swellable/soluble acrylic emulsion polymers (ASE), Hydrophobically-modified alkali-swellable/soluble acrylic emulsion polymers (HASE), and Hydrophobically-modified Ethoxylated URethane (HEUR) organic polymers, for example.

Alkali-Swellable/soluble Emulsion (ASE) rheology modifiers are dispersions of insoluble acrylic polymers in water have a high percentage of acid groups distributed throughout their polymer chains When these acid groups are neutralized, the salt that is formed is hydrated. Depending on the concentration of acid groups, the molecular weight and degree of crosslinking, the salt either swells in aqueous solutions or becomes completely water-soluble.

As the concentration of neutralized polymer in an aqueous formulation increases, the polymer chains swell, thereby causing the viscosity to increase.

ASE polymers can be synthesized from acid and acrylate co-monomers, and are generally made through emulsion polymerization. Exemplary commercially available ASE polymers include those available as ACUSOL 810A, ACUSOL 830, ACUSOL 835, ACUSOL 842, and ACRYSOL RM-38.

Hydrophobically-modified Alkali-Swellable/soluble Emulsion (HASE) polymers are commonly employed to modify the rheological properties of aqueous emulsion systems. Under the influence of a base, organic or inorganic, the HASE particles gradually swell and expand to form a three-dimensional network by intermolecular hydrophobic aggregation between HASE polymer chains and/or with components of the emulsion. This network, combined with the hydrodynamic exclusion volume created by the expanded HASE chains, produces the desired thickening effect. This network is sensitive to applied stress, breaks down under shear and recovers when the stress is relieved.

HASE rheology modifiers can be prepared from the following monomers: (a) an ethylenically unsaturated carboxylic acid, (b) a nonionic ethylenically unsaturated monomer, and (c) an ethylenically unsaturated hydrophobic monomer. Representative HASE polymer systems include those shown in EP 226097 B1 (van Phung et al.), EP 705852 B1 (Doolan et al.), U.S. Pat. No. 4,384,096 (Sonnabend) and U.S. Pat. No. 5,874,495 (Robinson).

Exemplary commercially available HASE polymers include those marketed by Dow Chemical under the trade designations ACUSOL 801S, ACUSOL 805S, ACUSOL 820, and ACUSOL 823.

ASE and HASE rheology modifiers are pH-triggered thickeners. Whether the emulsion polymer in each is water-swellable or water-soluble typically depends on its molecular weight. Both forms are acceptable. Further details concerning synthesis of ASE and HASE polymers can be found, for example, in U.S. Pat. No. 9,631,165 (Droege et al.).

Hydrophobically-modified Ethoxylated URethane (HEUR) polymers are generally synthesized from an alcohol, a diisocyanate and one or more polyalkylene glycols. HEURs are water-soluble polymers containing hydrophobic groups, and are classified as associative thickeners because the hydrophobic groups associate with one another in water. Unlike HASEs, HEURs are nonionic substances and are not dependent on alkali for activation of the thickening mechanism. They develop intra- or intermolecular links as their hydrophobic groups associate with other hydrophobic ingredients in a given formulation. As a general rule, the strength of the association depends on the number, size, and frequency of the hydrophobic capping or blocking units. HEURs develop micelles as would a normal surfactant. The micelles then link between the other ingredients by associating with their surfaces. This builds a three-dimensional network.

Exemplary commercially available HEUR polymers include those marketed by Dow Chemical under the trade designations ACUSOL 880, ACUSOL 882, ACRYSOL RM-2020, ACRYSOL RM-8W, and ACRYSOL RM-12W.

Further details concerning HEURs can be found, for example, in U.S. Pat. Appl. Publ. No. 2017/0198238 (Kensicher et al.) and 2017/0130072 (McCulloch et al.) and U.S. Pat. No. 7,741,402 (Bobsein et al.) and U.S. Pat. No. 8,779,055 (Rabasco et al.).

Once the make layer precursor is coated onto the backing, and before curing, abrasive particles are partially embedded in the make layer precursor. Curing of the make layer precursor then secures the abrasive particles in the make layer.

Useful abrasive particles may be the result of a crushing operation (e.g., crushed abrasive particles that have been sorted for shape and size) or the result of a shaping operation (i.e., shaped abrasive particles) in which an abrasive precursor material is shaped (e.g., molded), dried, and converted to ceramic material. Combinations of abrasive particles resulting from crushing with abrasive particles resulting from a shaping operation may also be used. The abrasive particles may be in the form of, for example, individual particles, agglomerates, composite particles, and mixtures thereof.

The abrasive particles should have sufficient hardness and surface roughness to function as crushed abrasive particles in abrading processes. Preferably, the abrasive particles have a Mohs hardness of at least 4, at least 5, at least 6, at least 7, or even at least 8.

Suitable abrasive particles include, for example, crushed abrasive particles comprising fused aluminum oxide, heat-treated aluminum oxide, white fused aluminum oxide, ceramic aluminum oxide materials such as those commercially available as 3M CERAMIC ABRASIVE GRAIN from 3M Company, St. Paul, Minn., brown aluminum oxide, blue aluminum oxide, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, garnet, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina zirconia, iron oxide, chromic, zirconia, titania, tin oxide, quartz, feldspar, flint, emery, sol-gel-derived ceramic (e.g., alpha alumina), and combinations thereof. Examples of sol-gel-derived abrasive particles from which the abrasive particles can be isolated, and methods for their preparation can be found, in U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951 (Monroe et al.). It is also contemplated that the abrasive particles could comprise abrasive agglomerates such, for example, as those described in U.S. Pat. No. 4,652,275 (Bloecher et al.) or U.S. Pat. No. 4,799,939 (Bloecher et al.). In some embodiments, the abrasive particles may be surface-treated with a coupling agent (e.g., an organosilane coupling agent) or other physical treatment (e.g., iron oxide or titanium oxide) to enhance adhesion of the crushed abrasive particles to the binder. The abrasive particles may be treated before combining them with the binder, or they may be surface treated in situ by including a coupling agent to the binder.

Preferably, the abrasive particles (and especially the abrasive particles) comprise ceramic abrasive particles such as, for example, sol-gel-derived polycrystalline alpha alumina particles. Ceramic abrasive particles composed of crystallites of alpha alumina, magnesium alumina spinel, and a rare earth hexagonal aluminate may be prepared using sol-gel precursor alpha alumina particles according to methods described in, for example, U.S. Pat. No. 5,213,591 (Celikkaya et al.) and U.S. Publ. Pat. Appln. Nos. 2009/0165394 A1 (Culler et al.) and 2009/0169816 A1 (Erickson et al.). Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Pat. No. 4,314,827 (Leitheiser); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,435,816 (Spurgeon et al.); U.S. Pat. No. 5,672,097 (Hoopman et al.); U.S. Pat. No. 5,946,991 (Hoopman et al.); U.S. Pat. No. 5,975,987 (Hoopman et al.); and U.S. Pat. No. 6,129,540 (Hoopman et al.); and in U.S. Publ. Pat. Appln. No. 2009/0165394 A1 (Culler et al.).

In some preferred embodiments, useful abrasive particles (especially in the case of the abrasive particles) may be shaped abrasive particles can be found in U.S. Pat. No. 5,201,916 (Berg); U.S. Pat. No. 5,366,523 (Rowenhorst (Re 35,570)); and U.S. Pat. No. 5,984,988 (Berg). U.S. Pat. No. 8,034,137 (Erickson et al.) describes alumina abrasive particles that have been formed in a specific shape, then crushed to form shards that retain a portion of their original shape features. In some embodiments, the abrasive particles are precisely-shaped (i.e., the particles have shapes that are at least partially determined by the shapes of cavities in a production tool used to make them. Details concerning such abrasive particles and methods for their preparation can be found, for example, in U.S. Pat. No. 8,142,531 (Adefris et al.); U.S. Pat. No. 8,142,891 (Culler et al.); U.S. Pat. No. 8,142,532 (Erickson et al.); U.S. Pat. No. 9,771,504 (Adefris); and in U.S. Pat. Appl. Publ. Nos. 2012/0227333 (Adefris et al.); 2013/0040537 (Schwabel et al.); and 2013/0125477 (Adefris). One particularly useful precisely-shaped abrasive particle shape is that of a platelet having three-sidewalls, any of which may be straight or concave, and which may be vertical or sloping with respect to the platelet base; for example, as set forth in the above cited references. An exemplary such precisely-shaped abrasive particle 200 is shown in FIG. 2 .

Surface coatings on the abrasive particles may be used to improve the adhesion between the abrasive particles and a binder material, or to aid in electrostatic deposition of the abrasive particles. In one embodiment, surface coatings as described in U.S. Pat. No. 5,352,254 (Celikkaya) in an amount of 0.1 to 2 percent surface coating to abrasive particle weight may be used. Such surface coatings are described in U.S. Pat. No. 5,213,591 (Celikkaya et al.); U.S. Pat. No. 5,011,508 (Wald et al.); U.S. Pat. No. 1,910,444 (Nicholson); U.S. Pat. No. 3,041,156 (Rowse et al.); U.S. Pat. No. 5,009,675 (Kunz et al.); U.S. Pat. No. 5,085,671 (Martin et al.); U.S. Pat. No. 4,997,461 (Markhoff-Matheny et al.); and U.S. Pat. No. 5,042,991 (Kunz et al.). Additionally, the surface coating may prevent shaped abrasive particles from capping. Capping is the term to describe the phenomenon where metal particles from the workpiece being abraded become welded to the tops of the abrasive particles. Surface coatings to perform the above functions are known to those of skill in the art.

In some embodiments, the abrasive particles may be selected to have a length and/or width in a range of from 0.1 micrometers to 3.5 millimeters (mm), more typically 0.05 mm to 3.0 mm, and more typically 0.1 mm to 2.6 mm, although other lengths and widths may also be used.

The abrasive particles may be selected to have a thickness in a range of from 0.1 micrometer to 1.6 mm, more typically from 1 micrometer to 1.2 mm, although other thicknesses may be used. In some embodiments, abrasive particles may have an aspect ratio (length to thickness) of at least 2, 3, 4, 5, 6, or more.

Abrasive particles may be independently sized according to an abrasives industry recognized specified nominal grade. Exemplary abrasive industry recognized grading standards include those promulgated by ANSI (American National Standards Institute), FEPA (Federation of European Producers of Abrasives), and JIS (Japanese Industrial Standard) Such industry accepted grading standards include, for example: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 30, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400, and ANSI 600; FEPA P8, FEPA P12, FEPA P16, FEPA P24, FEPA P30, FEPA P36, FEPA P40, FEPA P50, FEPA P60, FEPA P80, FEPA P100, FEPA P120, FEPA P150, FEPA P180, FEPA P220, FEPA P320, FEPA P400, FEPA P500, FEPA P600, FEPA P800, FEPA P1000, FEPA P1200; FEPA F8, FEPA F12, FEPA F16, and FEPA F24; and JIS 8, JIS 12, JIS 16, JIS 24, JIS 36, JIS 46, JIS 54, JIS 60, JIS 80, JIS 100, JIS 150, JIS 180, JIS 220, JIS 240, JIS 280, JIS 320, JIS 360, JIS 400, JIS 600, JIS 800, JIS 1000, JIS 1500, JIS 2500, JIS 4000, JIS 6000, JIS 8000, and JIS 10,000. More typically, the crushed aluminum oxide particles and the non-seeded sol-gel derived alumina-based abrasive particles are independently sized to ANSI 60 and 80, or FEPA F36, F46, F54 and F60 or FEPA P60 and P80 grading standards

Alternatively, the abrasive particles can be graded to a nominal screened grade using U.S.A. Standard Test Sieves conforming to ASTM E-11 “Standard Specification for Wire Cloth and Sieves for Testing Purposes”. ASTM E-11 prescribes the requirements for the design and construction of testing sieves using a medium of woven wire cloth mounted in a frame for the classification of materials according to a designated particle size. A typical designation may be represented as −18+20 meaning that the shaped abrasive particles pass through a test sieve meeting ASTM E-11 specification for the number 18 sieve and are retained on a test sieve meeting ASTM E-11 specification for the number 20 sieve. In one embodiment, the shaped abrasive particles have a particle size such that most of the particles pass through an 18 mesh test sieve and can be retained on a 20, 25, 30, 35, 40, 45, or 50 mesh test sieve. In various embodiments, the shaped abrasive particles can have a nominal screened grade comprising: −18+20, −20+25, −25+30, −30+35, −35+40, −40+45, −45+50, −50+60, −60+70, −70+80, −80+100, −100+120, −120+140, −140+170, −170+200, −200+230, −230+270, −270+325, −325+400, −400+450, −450+500, or −500+635. Alternatively, a custom mesh size could be used such as −90+100.

The size layer is generally formed by coating and at least partially curing a size layer precursor comprising a thermosetting/curable composition over the at least partially cured make layer and abrasive particles and at least partially curing the size layer precursor. Suitable size layer precursor/size layers may have the same or different composition described above for inclusion in the make layer precursor/make layer.

In some embodiments, the size layer precursor comprises a resole phenolic resin and an organic polymeric rheology modifier as described hereinbefore in the case of the make layer precursor/make layer.

The supersize layer precursor comprises a water-based epoxy resin and an organic polymeric rheology modifier as described hereinabove.

Exemplary water-based epoxy resins and precursors (e.g., water-dispersible epoxy resins) thereof include: epoxy resins marketed by Hexion, Columbus, Ohio, such as EPI-REZ Resin WD-510 water dispersible liquid resin, and resin dispersions under the trade designations EPI-REZ Resin 3510-W-60 and EPI-REZ Resin 7510-W-60, EPI-REZ Resin 3515-W-60, EPI-REZ Resin 3520-WY-55, EPI-REZ Resin 6520-WH-53, EPI-REZ Resin 7520-WD-52, EPI-REZ Resin 3522-W-60, EPI-REZ Resin 3540-WY-55, EPI-REZ Resin 3546-WH-53, EPI-REZ Resin 5520-W-60, EPI-REZ Resin 5522-WY-55, EPI-REZ Resin 5003-W-55, EPON Resin RSW-2801, EPI-REZ Resin 5108-W-60, and EPI-REZ Resin 6006-W-68; epoxy resins marketed by Olin Corp., Clayton, Mo., under the trade designations D.E.R. 900, D.E.R. 913, D.E.R. 915, D.E.R. 916, and D.E.R. 917; and from Allnex Corp., Frankfurt, Germany, under the trade designations BECKOPDX VEP 2381 W/55WA. Some preferred water-based epoxy resins include diglycidyl ethers of bisphenol A.

In some embodiments, the supersize layer is formed from a composition containing a water-based epoxy resin, nonionic emulsifier, water, an imidazole curing agent, potassium tetrafluoroborate grinding aid, and a dispersing agent. Once the epoxy dispersion has been applied to the coated abrasive product, it can be heated to bring about polymerization of the epoxy resin. Heating is typically conducted for a period of from about 10 to about 250 minutes, preferably from about 20 to about 50 minutes, at temperatures from about 80° C. to about 130° C., preferably from about 105° C. to about 115° C. Further details concerning water-based epoxy resins and supersize layers containing them can be found in, for example, U.S. Pat. No. 5,556,437 (Lee et al.)

Typically, the supersize layer also contains at least one grinding aid however this is not a requirement.

A grinding aid is a material that has a significant effect on the chemical and physical processes of abrading, which results in improved performance. Grinding aids encompass a wide variety of different materials and can be inorganic or organic based. Examples of chemical groups of grinding aids include waxes, organic halide compounds, halide salts, metals and their alloys, and stearates and metal salts of stearates. The organic halide compounds will typically break down during abrading and release a halogen acid or a gaseous halide compound. Examples of such materials include chlorinated waxes like tetrachloronaphthalene, pentachloronaphthalene, and polyvinyl chloride. Examples of halide salts include sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluorides, potassium chloride, and magnesium chloride. Examples of metals include, tin, lead, bismuth, cobalt, antimony, cadmium, iron, and titanium.

Other miscellaneous grinding aids include sulfur, organic sulfur compounds, graphite, and metallic sulfides. A combination of different grinding aids may be used, and in some instances, this may produce a synergistic effect.

Grinding aids can be particularly useful in coated abrasives. In coated abrasive articles, grinding aid is typically used in a supersize layer, which is applied over the surface of the size layer. Sometimes, however, the grinding aid is added to the size layer. Typically, the amount of grinding aid incorporated into coated abrasive articles are about 50-800 grams per square meter (g/m²), preferably about 80-475 g/m², however, this is not a requirement.

The supersize layer typically has a basis weight of 5 to 1100 grams per square meter (gsm), preferably 50 to 700 gsm, and more preferably 250 to 600 gsm, although this is not a requirement. The basis weight of the make layer, size layer, and optional supersize layer typically depend at least in part on the abrasive particle size grade and the particular type of abrasive article.

The make layer, size layer, and supersize layer are formed by at least partially curing corresponding precursors (i.e., a make layer precursor, a size layer precursor, a supersize layer precursor).

The make layer, size layer, and supersize layer and their precursors may also contain additives such as fibers, lubricants, wetting agents, surfactants, pigments, dyes, antistatic agents (e.g., carbon black, vanadium oxide, and/or graphite), coupling agents (e.g., silanes, titanates, and/or zircoaluminates), plasticizers, suspending agents, and the like. The amounts of these optional additives are selected to provide the preferred properties. The coupling agents can improve adhesion to the abrasive particles and/or filler. The curable composition may be thermally-cured, radiation-cured, or a combination thereof.

The make layer, size layer, and supersize layer and their precursors may also contain filler materials, diluent abrasive particles (e.g., as described hereinbelow), or grinding aids, typically in the form of a particulate material. Typically, the particulate materials are inorganic materials. Examples of useful fillers for this disclosure include: metal carbonates (e.g., calcium carbonate (e.g., chalk, calcite, marl, travertine, marble and limestone), calcium magnesium carbonate, sodium carbonate, magnesium carbonate), silica (e.g., quartz, glass beads, glass bubbles and glass fibers) silicates (e.g., talc, clays, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate) metal sulfates (e.g., calcium sulfate, barium sulfate, sodium sulfate, aluminum sodium sulfate, aluminum sulfate), gypsum, vermiculite, wood flour, aluminum trihydrate, carbon black, metal oxides (e.g., calcium oxide (lime), aluminum oxide, titanium dioxide), and metal sulfites (e.g., calcium sulfite).

Further details regarding coated abrasive articles and methods of their manufacture can be found, for example, in U.S. Pat. No. 4,734,104 (Broberg); U.S. Pat. No. 4,737,163 (Larkey); U.S. Pat. No. 5,203,884 (Buchanan et al.); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,378,251 (Culler et al.); U.S. Pat. No. 5,436,063 (Follett et al.); U.S. Pat. No. 5,496,386 (Broberg et al.); U.S. Pat. No. 5,609,706 (Benedict et al.); U.S. Pat. No. 5,520,711 (Helmin); U.S. Pat. No. 5,961,674 (Gagliardi et al.), and U.S. Pat. No. 5,975,988 (Christianson).

Coated abrasive articles according to the present disclosure are useful, for example, for abrading a workpiece. Such a method may comprise frictionally contacting an abrasive article according to the present disclosure with a surface of the workpiece, and moving at least one of the coated abrasive article and the surface of the workpiece relative to the other to abrade at least a portion of the surface of the workpiece. Methods for abrading with coated abrasive articles according to the present disclosure include, for example, snagging (i.e., high-pressure high stock removal) to polishing (e.g., polishing medical implants with coated abrasive belts), wherein the latter is typically done with finer grades (e.g., ANSI 220 and finer) of abrasive particles. The size of the abrasive particles used for a particular abrading application will be apparent to those skilled in the art.

Abrading may be carried out dry or wet. For wet abrading, the liquid may be introduced supplied in the form of a light mist to complete flood. Examples of commonly used liquids include water, water-soluble oil, organic lubricant, and emulsions. The liquid may serve to reduce the heat associated with abrading and/or act as a lubricant. The liquid may contain minor amounts of additives such as bactericide, antifoaming agents, and the like.

Examples of workpieces include aluminum metal, carbon steels, mild steels (e.g., 1018 mild steel and 1045 mild steel), tool steels, stainless steel, hardened steel, titanium, glass, ceramics, wood, wood-like materials (e.g., plywood and particle board), paint, painted surfaces, and organic coated surfaces. The applied force during abrading typically ranges from about 1 to about 100 kilograms (kg), although other pressures can also be used.

SELECT EMBODIMENTS OF THE PRESENT DISCLOSURE

In a first embodiment, the present disclosure provides a method of making a coated abrasive article, the method comprising:

-   -   providing a backing having first and second opposed major         surfaces, wherein a make layer is disposed on at least a portion         of the first major surface and bonds abrasive particles to the         backing, and further wherein a size layer is disposed over at         least a portion of the make layer and the abrasive particles;         and     -   coating a supersize layer precursor over at least a portion of         the size layer and at least partially curing the supersize layer         precursor to provide a supersize layer,     -   wherein the supersize layer precursor comprises a water-based         epoxy resin and an organic polymeric rheology modifier, wherein         the organic polymeric rheology modifier comprises an         alkali-swellable/soluble polymer, and, wherein on a solids         basis, the amount of the water-based epoxy resin comprises from         75 to 99.99 weight percent of the combined weight of the         water-based epoxy resin and the organic polymeric rheology         modifier.

In a second embodiment, the present disclosure provides a method according to the first embodiment, wherein said at least partially curing the supersize layer precursor occurs in a festoon oven.

In a third embodiment, the present disclosure provides a method according to the first or second embodiment, wherein the supersize layer precursor has a basis weight of 5 to 1100 grams per square meter.

In a fourth embodiment, the present disclosure provides a method according to any of the first to third embodiments, wherein the organic polymeric rheology modifier is selected from the group consisting of alkali-swellable/soluble acrylic polymers, hydrophobically-modified alkali-swellable/soluble acrylic polymers, hydrophobically-modified ethoxylated urethane polymers, and combinations thereof.

In a fifth embodiment, the present disclosure provides a method according to any of the first to fourth embodiments, wherein, on a solids basis, the amount of the water-based epoxy resin comprises from 85 to 99.99 weight percent of the combined weight of the water-based epoxy resin and the organic polymeric rheology modifier.

In a sixth embodiment, the present disclosure provides a method according to any of the first to fifth embodiments, wherein the abrasive particles comprise shaped abrasive particles.

In a seventh embodiment, the present disclosure provides a method according to the sixth embodiment, wherein the shaped abrasive particles comprise precisely-shaped abrasive particles.

In an eighth embodiment, the present disclosure provides a method according to the sixth embodiment, wherein the shaped abrasive particles comprise precisely-shaped three-sided platelets.

In a ninth embodiment, the present disclosure provides a coated abrasive article comprising:

-   -   a backing having first and second opposed major surfaces,     -   a make layer disposed on at least a portion of the first major         surface and bonding abrasive particles to the backing;     -   a size layer overlaid on at least a portion of the make layer         and the abrasive particles; and     -   a supersize layer disposed on the size layer,     -   wherein the supersize layer comprises an at least partially         cured epoxy resin and an organic polymeric rheology modifier,         and wherein the amount of the at least partially cured epoxy         resin comprises from 75 to 99.99 weight percent of the combined         weight of the at least partially cured epoxy resin and the         organic polymeric rheology modifier.

In a tenth embodiment, the present disclosure provides a coated abrasive article according to the ninth embodiment, wherein the organic polymeric rheology modifier is selected from the group consisting of alkali-swellable/soluble acrylic polymers, hydrophobically-modified alkali-swellable/soluble acrylic polymers, hydrophobically-modified ethoxylated urethane polymers, and combinations thereof.

In an eleventh embodiment, the present disclosure provides a coated abrasive article according to the ninth or tenth embodiment, wherein the amount of the at least partially epoxy resin comprises from 85 to 99.99 weight percent of the combined weight of the at least partially cured epoxy resin and the organic polymeric rheology modifier.

In a twelfth embodiment, the present disclosure provides a coated abrasive article according to any of the ninth to eleventh embodiments, wherein the abrasive particles comprise shaped abrasive particles.

In a thirteenth embodiment, the present disclosure provides a coated abrasive article according to the twelfth embodiment, wherein the shaped abrasive particles comprise precisely-shaped abrasive particles.

In a fourteenth embodiment, the present disclosure provides a coated abrasive article according to the twelfth embodiment, wherein the shaped abrasive particles comprise precisely-shaped three-sided platelets. Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

Examples

Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight. Table 1, below reports materials used in the Examples.

TABLE 1 ABBREVIATION DESCRIPTION AND SOURCE PF Resole resin (75 wt. % in water), a phenol:formaldehyde (molar ratio of 1:1.5 to 1:2.1) condensate catalyzed by 1 to 5% metal hydroxide. Obtained from Georgia Pacific, Atlanta, Georgia. ER A 60% solids epoxy resin dispersion commercially available as EPIREZ 3520 W60 from Hexion, Columbus, Ohio. LR A 53% solids latex dispersion obtained commercially as SURETAC 1585 from Dyna-Tech Adhesives Inc., Grafton, West Virginia. ADD1 Hydrophobically modified ethoxylated urethane polymers (HEUR) obtained as ACRYSOL 8W from The Dow Chemical Company, Midland, Michigan. Obtained as an aqueous emulsion with 17.5% solids content. ADD2 Hydrophobically modified ethoxylated urethane polymers (HEUR) obtained as ACRYSOL 12W from The Dow Chemical Company. Aqueous emulsion with 19% solids content. ADD3 An alkali-swellable acrylic polymer emulsion (ASE) obtained as ACUSOL 835 from The Dow Chemical Company. Aqueous emulsion with 28.75% solids content. ADD4 Hydrophilic amorphous fumed silica obtained as CAB-O-SIL M-5 from Cabot Corporation, Alpharetta, Georgia. ADD5 Red iron oxide pigment obtained as KROMA RO-3097 from Elementis, East Saint Louis, Illinois. ADD6 2,4,Diethylimidaozle obtained as 2,4 EMI from Air Products, Allentown, Pennsylvania. FIL1 Calcium silicate obtained as M400 WOLLASTOCOAT from NYCO, Willsboro, New York. FIL2 Cryolite obtained as CRYOLITE RTN-C from FREEBEE A'S, Ullerslev, Denmark. FIL3 Potassium tetrafluoroborate obtained from A WSM industries, Paramus, New Jersey. SF1 Surfactant obtained as AEROSOL OT-NV, from Cytec-Solvay Group, Stamford, Connecticut. SF2 Surfactant obtained as FOAMSTAR ST 2425 (formerly ST 125), from BASF Corporation, Florham Park, New Jersey. SAP1 Shaped abrasive particles were prepared according to the disclosure of U.S. Pat. No. 8,142,531 (Adefris et al). The shaped abrasive particles were prepared by molding alumina sol gel in equilateral triangle-shaped polypropylene mold cavities. After drying and firing, the resulting shaped abrasive particles, which were shaped as truncated triangular pyramids, were about 1.4 mm (side length) × 0.35 mm (thickness), with a draft angle approximately 98 degrees.

Preparation of Resins Comparative Supersize Layer Precursor CSSR-A

A 3-Liter plastic container was charged with 438.grams of ER, 173 grams of water, 8.7 grams of ADD4, 55.1 grams of ADD 5, 13.8 grams of ADD 6, 18.1 grams of SF1, 1.9 grams of SF2 and 319.4 grams of LR, and then mixed for 10 minutes with an overhead mechanical stirrer. Next, 1972 grams of FIL2 was added over a 15-minute period. The resultant mixture was stirred for 15 minutes with an overhead stirrer.

Comparative Supersize Layer Precursors CSSR-B, CSSR-C, CSSR-D, and CSSR-E

A 118-ml glass jar was charged with 99.5 grams of CSSR-A and 0.25 grams of FIL1. The mixture was stirred for 5 minutes with an overhead stirrer to make Comparative Supersize Layer Precursor CSSR-B. Comparative Supersize Layer Precursors CSSR-C, CSSR-D, and CSSR-E were prepared in similar fashion and formulations are described in Table 2.

Supersize Layer Precursors ESSR-1 and ESSR-2

A 118-ml glass was charged with 99.5 grams CSSR-A and 0.5 gram ADD 2. The mixture was stirred for 5 minutes with an overhead sitter to make Supersize Layer Precursor 1 (ESSR-1). Example Supersize Layer Precursor 2 (ESSR-2) was prepared in similar fashion and formulation is described in Table 2.

Supersize Layer Precursors ESSR-3 and ESSR-4

A 118-ml glass jar was charged with 99.5 grams of CSSR-A and 0.5 grams of ADD The mixture was stirred for 5 minutes with an overhead stirrer to make Supersize Layer Precursor ESSR-3. Supersize Layer Precursor ESSR-4 example was prepared in similar fashion and formulation is described in Table 2, below.

TABLE 2 SUPERSIZE CSSR-A, ADD1, ADD2, LAYER CSSR-A, grams of ADD1, grams of ADD2, grams of ADD4, PRECURSOR grams solids grams solids grams solids grams CSSR-A 100 83.07 CSSR-B 99.75 82.862 0.25 CSSR-C 99.5 82.654 0.5 CSSR-D 99.25 82.447 0.75 CSSR-E 99 82.239 1 ESSR-1 99.5 82.654 0.5 0.0875 ESSR-2 99 82.239 1 0.175 ESSR-3 99.5 82.654 0.5 0.095 ESSR-4 99 82.239 1 0.19

Incline Plane Flow Test

The Incline Plane Flow Test involves placing 0.1 gram drop of resin at specified temperature onto a horizontally positioned glass slide and then quickly tilting glass slide on incline device set at 48.7° angle for one minute (see Graphs 1,2 and Table 2,3). The distance the resin travels in one minute is recorded in millimeters (mm). The smaller the distance the less likely the resin will have excessive flow and cause bottom loop puddling in the festoon curing ovens. The analysis of data (Graphs, 1,2 and Table 2,3) clearly illustrate the thixotropic nature of ESSR-1, 2, 3, and 4. In fact, these examples show 10×-20× improvement over Comparative Examples (CSSR-A, B, C, and D) on a 100% solids weight basis.

TABLE 3, below shows Inclined Plane Flow Test results for various resins at room temperature (RT) and 41° C.

TABLE 3 INCLINED PLANE FLOW TEST, millimeters RESIN RT 41° C. ESSR-1 3 0 ESSR-2 0 0 ESSR-3 4 0 ESSR-4 4 0 CSSR-A 24 28 CSSR-B not measured 10 CSSR-C not measured 5 CSSR-D not measured 0

Make Resin MR

The make resin was prepared charging a 17-liter pail with 7812 grams of PF, 6823 grams of FILL and 364 grams for water. The resin was mixed with an overhead stirrer for 30 minutes at room temperature.

Size Resin SR1

The size resin was prepared charging a 17-liter pail with 11100 grams of PF, 5800 grams of FIL 1, 5800 grams of FIL 1, 420 grams of ADD5, and 2000 grams of water. The resin was mixed with an overhead stirrer for 30 minutes at room temperature.

Size Resin SR2

The size resin was prepared charging a 17-liter pail with 11100 grams of PF, 5800 grams of FIL 1, 5800 grams of FIL 1, 420 grams of ADD5, 118 grams of ADD3, and 2000 grams of water. The resin was mixed with an overhead stirrer for 30 minutes at room temperature.

Supersize Layer Precursor ESSR-5

The Example Supersize Layer Precursor ESSR-5 was prepared by charging a 17-liter pail with 18180 grams of CSSR-A, 92 grams of ADD2, 92 grams of ADD3 and 614 grams of water, mixed for 30 of minutes with an overhead mechanical stirrer.

Coated Abrasive Comparative Supersize CSSR-F

Coated abrasive examples and comparative examples were prepared by roll coating make resin MR onto a continuous 30.48 cm wide polyester backing (described in Example 12 of U.S. Pat. No. 6,843,815 Thurber et al.) at a coating weight of 210 grams per square meter (gsm) followed by electrostatically coating mineral SAP1 at a weight of 605 gsm. The coated material was cured at 90° C. for 90 minutes and at 102° C. for 60 minutes. The resultant material was then roll coated with size resin SR1 and a coat weight of 567 grams per square meter (gsm). The material was cured at 90° C. for 60 minutes and at 102° C. for 60 minutes. The resultant material was then roll coated with comparative Supersize Layer Precursor CS SR-A at a coat weight of 567 grams per square meter (gsm). The material was final cured at 90° C. for 60 minutes at 102° C. for 12 hours and at 109° C. for 1 hour.

Coated Abrasive Example Supersize ESSR-5

Coated abrasive examples and comparative examples were prepared by roll coating make resin MR onto a continuous 30.48 cm wide polyester backing (described in Example 12 of U.S. Pat. No. 6,843,815 (Thurber et al.)) at a coating weight of 210 grams per square meter (gsm) followed by electrostatically coating mineral SAP1 at a weight of 605 gsm. The coated material was cured at 90° C. for 90 minutes and at 102° C. for 60 minutes. The resultant material was then roll coated with size resin SR2 and a coat weight of 567 grams per square meter (gsm). The material was cured at 90° C. for 60 minutes and at 102° C. for 60 minutes. The resultant material was then roll coated with comparative Supersize Layer Precursor ESSR-5 at a coat weight of 567 grams per square meter (gsm). The material was final cured at 90 C for 60 minutes at 102° C. for 12 hours and at 109° C. for 1 hour.

Comparison of Coated Abrasive Supersize Layer Precursors

As shown in FIGS. 3 and 4 , a coated abrasive article made using Comparative Supersize Layer Precursor CSSR-F (shown in FIG. 3 ) displayed bottom loop puddling issues, while the same coated abrasive article, except using Supersize Layer Precursor ESSR-5 (shown in FIG. 4 ) did not.

All cited references, patents, and patent applications in this application that are incorporated by reference, are incorporated in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in this application shall control. The preceding description, given in order to enable one of ordinary skill in the art to practice the claimed disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereto. 

What is claimed is:
 1. A method of making a coated abrasive article, the method comprising: providing a backing having first and second opposed major surfaces, wherein a make layer is disposed on at least a portion of the first major surface and bonds abrasive particles to the backing, and further wherein a size layer is disposed over at least a portion of the make layer and the abrasive particles; and coating a supersize layer precursor over at least a portion of the size layer and at least partially curing the supersize layer precursor to provide a supersize layer, wherein the supersize layer precursor comprises a water-based epoxy resin and an organic polymeric rheology modifier, wherein the organic polymeric rheology modifier comprises an alkali-swellable/soluble polymer, and, wherein on a solids basis, the amount of the water-based epoxy resin comprises from 75 to 99.99 weight percent of the combined weight of the water-based epoxy resin and the organic polymeric rheology modifier.
 2. The method of claim 1, wherein said at least partially curing the supersize layer precursor occurs in a festoon oven.
 3. The method of claim 1, wherein the supersize layer precursor has a basis weight of 5 to 1100 grams per square meter.
 4. The method of claim 1, wherein the organic polymeric rheology modifier is selected from the group consisting of alkali-swellable/soluble acrylic polymers, hydrophobically-modified alkali-swellable/soluble acrylic polymers, hydrophobically-modified ethoxylated urethane polymers, and combinations thereof.
 5. The method of claim 1, wherein, on a solids basis, the amount of the water-based epoxy resin comprises from 85 to 99.99 weight percent of the combined weight of the water-based epoxy resin and the organic polymeric rheology modifier.
 6. The method of claim 1, wherein the abrasive particles comprise shaped abrasive particles.
 7. The method of claim 6, wherein the shaped abrasive particles comprise precisely-shaped abrasive particles.
 8. The method of claim 6, wherein the shaped abrasive particles comprise precisely-shaped three-sided platelets.
 9. A coated abrasive article comprising: a backing having first and second opposed major surfaces, a make layer disposed on at least a portion of the first major surface and bonding abrasive particles to the backing; a size layer overlaid on at least a portion of the make layer and the abrasive particles; and a supersize layer disposed on the size layer, wherein the supersize layer comprises an at least partially cured epoxy resin and an organic polymeric rheology modifier, and wherein the amount of the at least partially cured epoxy resin comprises from 75 to 99.99 weight percent of the combined weight of the at least partially cured epoxy resin and the organic polymeric rheology modifier.
 10. The coated abrasive article of claim 9, wherein the organic polymeric rheology modifier is selected from the group consisting of alkali-swellable/soluble acrylic polymers, hydrophobically-modified alkali-swellable/soluble acrylic polymers, hydrophobically-modified ethoxylated urethane polymers, and combinations thereof.
 11. The coated abrasive article of claim 9, wherein the amount of the at least partially epoxy resin comprises from 85 to 99.99 weight percent of the combined weight of the at least partially cured epoxy resin and the organic polymeric rheology modifier.
 12. The coated abrasive article of claim 9, wherein the abrasive particles comprise shaped abrasive particles.
 13. The coated abrasive article of claim 12, wherein the shaped abrasive particles comprise precisely-shaped abrasive particles.
 14. The coated abrasive article of claim 12, wherein the shaped abrasive particles comprise precisely-shaped three-sided platelets. 